How it work:

It works like other recuperation unit, air go out charge something and when getting back is heated with "something" As something I use couple spring stateliness dish clearing tools.

Because I have no way how to change direction of DC fans I use two in opposite direction.

And small board for switching and display time

- 60 second out

- 60 second in

There is lot space for tweaking, sensor an more.

I think we need some measurements, but unfortunately for this measurements is summer near a and outside

temperature is almost same like outside.